DR. SHAILESH K. KOHAD

ANAESTHESIA SPECIALIST

KING SAUD MEDICAL CITY, RIYADH.

ANATOMY

PHYSIOLOGY

AIRWAY ASSESSMENT

AIRWAY MANAGEMENT

DIFFICULT AIRWAY MANAGEMENT

UNANTICIPATED DIFFICULT AIRWAY

AIRWAY MANAGEMENT IN SPECIAL CASES

Relatively large

Anterior flexion may cause airway obstruction

Obligate Nasal Breathers

Poor tolerance to obstruction

Relatively Large

Obstructs Airway

Neck extension may not relieve obstruction

Difficult to visualize larynx

Adult epiglottis broader, axis parallel to trachea

Infant epiglottis omega shaped and axis angled away from trachea

More difficult to lift an infant’s epiglottis with laryngoscope blade

Straight laryngoscope blade completely elevates the epiglottis, preferred for pediatric laryngoscopy

More susceptible to trauma

Laryngeal apparatus develops from brachial clefts and descends caudally hence Infant’s larynx is higher in neck (C2-3) compared to adult’s (C4-5)

More Anterior

Intubation more difficult

Infant’s vocal cords have more angled attachment to trachea, whereas adult vocal cords are more perpendicular

Difficulty in nasal intubations where “blindly” placed ETT may easily lodge in anterior commissure rather than in trachea

Narrowest portion

↑ resistance with airway edema or infection

Acts as “cuff” during tracheal intubation

Tight fitting ETT may cause edema and trouble upon extubation

Uncuffed ETT preferred for children < 8 years old

Fully developed cricoidcartilage occurs at 10-12 years of age

Funnel shaped

Small diameter (6mm), high compliance

↑ resistance with airway edema or infection

Collapses easily with neck hyperflexion or hyperextension

Alveoli ↑ Closing Capacity & ↑ air trapping

Pulmonary Vessels ↑ Pulmonary vascular resistance

(PVR) Very sensitive to constriction by

hypoxia, acidosis and hypercarbia

Chest Wall Horizontal ribs ↑ A-P diameter ↑ compliance due to weak rib cage Breathing is all diaphragmatic FRC determined solely by elastic

recoil of lungs Chest wall collapses with negative

pressures

Compared to Adults Larger occiput

Nasal Breathers

Larger tongue

Epiglottis is floppier

Larynx Anterior & Cephalad

Funnel shaped Trachea

Cricoid Cartilage Narrowest

Type I & II pulmonary epithelial cells Pulmonary surfactant produced by Type II

pneumocytes at 24 wks GA Sufficient surfactant present after 35 wks GA Premature infants prone to respiratory

distress syndrome (RDS) because of insufficient surfactant

Betamethasone can be given to pregnant mothers at 24-35 wks GA to accelerate fetal surfactant production

High metabolic rate (5-8 ml/kg/min) Oxygen consumption of infant (6 ml/kg/min) is twice that

of an adult (3 ml/kg/min) [Less Oxygen Reserve] Tidal volume is relatively fixed (6-7 ml/kg/min) Minute Alveolar Ventilation is more dependent on

increased Respiratory Rate than on Tidal Volume Ratio of Alveolar Minute Ventilation to FRC is doubled

under circumstances of hypoxia, apnea or anesthesia Lung compliance is less while chest wall compliance is

more than those in adults - Reduced FRC and Atelectasis. Infant’s FRC is diminished and de-saturation occurs more

precipitously Lack Type I muscle fibers, fatigue more easily Prone to Bradycardia - Laryngeal stimulation and hypoxia

Poiseuille’s law: R = 8nl/ πr4

Best to 1st look from afar

Is the chest moving?

Can you hear breath sounds?

Are there any abnormal airway sounds (e.g.. Stridor, snoring)?

Is there increased respiratory effort with retractions or respiratory effort with no airway or breath sounds?

URTI - cough, laryngospasm, bronchospasm, desaturation during anesthesia

Snoring – Adenoid Hypertrophy, OSA, Upper Airway Obstruction Chronic Cough – Subglottic Stenosis, Previous Tracheoesohageal Fistula

Repair Productive Cough - Bronchitis, Pneumonia Sudden Onset of New Cough – Foreign Body Aspiration Inspiratory Stridor - Macroglossia, Laryngeal Web, Laryngomalacia,

Extrathoracic Foreign Body Hoarse Voice - Laryngitis, Vocal Cord Palsy, Papillomatosis Asthma - Bronchospasm Repeated Pneumonias - GERD, CF, Bronchiectasis, Tracheoesophageal

Fistula, Immune Suppression, Congenital Heart Disease Previous Anesthetic Problems Atopy, Allergy – Increased Airway Reactivity Congenital Syndrome - Pierre Robin Sequence, Treacher Collins, Klippel-

Feil, Down’s Syndrome, Choanal atresia Environmental Smokers

Facial expression

Nasal flaring

Mouth breathing

Color of mucous membranes

Retractions (suprasternal, intercostal, subcostal)

Respiratory rate

Voice change

Mouth opening

Size of mouth

Mallampati

Loose or missing teeth.

Size and configuration of palate.

Size and configuration of mandible (side view).

Presence of inspiratory stridor: Epiglottitis, croup, extrathoracic foreign body.

Both inspiratory and expiratory stridor: Aspirated foreign body, vascular ring, or large esophageal foreign body.

Prolonged expiration: lower airway disease?

Baseline oxygen saturation in room air.

Laboratory and radiographic evaluation extremely helpful with pathologic airway

AP and lateral films and fluoroscopy may show site and cause of upper airway obstruction

MRI/CT more reliable for evaluating neck masses, congenital anomalies of the lower airway and vascular system

Perform radiograph exam only when there is no immediate threat to the child’s safety and in the presence of skilled personnel with appropriate equipment to manage the airway

Intubation must not be postponed to obtain radiographic diagnosis when the patient is severely compromised.

Blood gases are helpful in assessing the degree of physiologic compromise; however, performing an arterial puncture on a stressed child may aggravate the underlying airway obstruction

Simple things to improve airway patency Suction nose and

oropharynx

Reposition child/ allow child to assume position of comfort

Head-tilt-chin lift/ jaw thrust

Use airway adjuncts- NPA/ OPA

Bag and Mask Ventilation

Intubation

S: Suction Catheters (6 - 16 french) and Yankauer tips (two sizes)

O: Oxygen and how to deliver Nasal cannula, oxygen flow, masks and appropriate bag

A: Airway Appropriate ETT, oral/nasal airway, stylets, laryngoscopes

P: Pharmacology RSI meds

ME: Monitoring Equipment EtCO2 detector, stethescope, monitors

Measure length - Pt’s earlobe to tip of nose

Duration < 10 sec.

May result in Hypoxia, ↓ HR (vagal), Bronchospasm, Larygospasm, Atelectasis

Appropriate suction catheter size

Neonates 5-6 Fr

Infants 6-8 Fr

Older kids 10 Fr

AgePressure

(mmHg)

< 1 yr 60-80

1-12 yrs 80-120

13-17 yrs 100-150

Oral

Nasal

Correct size Incorrect size

• Too small: will not adequately displace tongue• Too large: may obstruct larynx and/ or interfere with

mask fit

Place OPA against side of face. With flange at the corner of the mouth the tip should reach angle of the jaw

• Distance from nares to angle of mandible approximates the proper length• Nasopharyngeal airway available in 12F to 36F sizes• Shortened endotracheal tube may be used in infants or small children• Avoid placement in cases of hypertrophied adenoids - bleeding and

trauma

•Clear, plastic mask with inflatable rim provides atraumatic seal

•Proper area for mask application-bridge of nose extend to chin

•Maintain airway pressures <20 cm H2O

•Place fingers on mandible to avoid compressing pharyngeal space•Hand on ventilating bag at all times to monitor effectiveness of spontaneous breaths•Continous postitive pressure when needed to maintain airway patency

3 sizes:

Age Volume (ml)

Infant 500

Child 1000

Adolescent 2000

Goals of Larynoscopy

The problem is…

…but we are here.

Cords are here…

The aim is…

To “see around the corner”

• The goal of DL…

• To get rid of the corner

• To create straight line of

sight

Oral axis

Pharyngeal axis

Tracheal axis

Oral

Pharyngeal

Tracheal

Straight blades are placed under the epiglottis and used to lift anteriorly to expose the cords.

Curved blades are placed in the valecula and lifted anteriorly to expose the cords.

Macintosh

Miller

Wisconsin

Miller blade is preferred for infants and younger children

Facilitates lifting of the epiglottis and exposing the glottic opening

Care must be taken to avoid using the blade as a fulcrum with pressure on the teeth and gums

Macintosh blades are generally used in older children

Age Blade/Size

Infant Miller 1

2 years old Miller 2

12 years old Miller/Mac 3

“Switch to a 2 at 2”

For neonates endotracheal tube size roughly corresponds to 1/10th of gestational age rounded down to the nearest size. For example

A 36 week premie would get a 3.5 ETT

A 28 week premie would get a 2.5 ETT

AgeETT Size (ID)

(mm)ETT Length

(cm)

> 6 months 3 – 3.5 10

6 months – 1 yr 3.5 – 4.0 11

1 yr – 2 yr 4.0 – 5.0 12

SIZE

Uncuffed ET tube: (Age in years / 4) + 4

Uncuffed ET tube: (Age in years + 16) / 4

(rounded to nearest 0.5 mm)

Cuffed ET tube: (Age in years / 4) + 3

LENGTH

ET tube Depth (Lip): ET tube Size (ID) x 3

ET tube Depth (Lip): (Age in yrs / 2) + 12

Uncuffed ETT recommended in children < 8 yrs old to avoid post-extubation stridor and subglottic stenosis

Cuffed ETT preferable in cases of: High risk of Aspiration (ie. Bowel obstruction) Low Lung Compliance (ie. ARDS, pneumoperitoneum, CO2

insufflation of the thorax, CABG) Precise control of Ventilation and pCO2 (ie. increased intracranial

pressure, single ventricle physiology)

Disadvantages of cuffed ETT: smaller size increases airway resistance, increase work of breathing, poorly designed for pediatric pts, need to keep cuff pressure < 25 cm H2O

Disadvantages of uncuffed ETT: more tube changes for long-term intubation, leak of anesthetic agent into environment, require more fresh gas flow > 2L/min, higher risk for aspiration

For “short” cases when ETT size > 4.0, choice of cuff vs uncuffedprobably does not matter

Remember DOPE

D Displaced ETTETT may be in trachea or in

right or left mainstem bronchus

OObstruction of

ETTSecretions, blood, pus,

foreign body, kinked ETT

P PneumothoraxSimple

Tension

EEquipment

failure

Disconnection of O2 source, leak in vent circuit, loss of power/ vent malfunction

Use largest size that can pass easily down the ETT

Ideally not larger than half the diameter of ETT to avoid causing atelectasis

TIP: choose double the ETT

e.g. 4.0 i.d. ETT choose 8 Fr suction catheter

Postintubation Croup Incidence 0.1-1%

Risk factors: large ETT, change in patient position introp, patient position other than supine, multiple attempts at intubation, traumatic intubation, pts ages 1-4, surgery >1hr, coughing on ETT, URI, h/o croup

Tx: humidified mist, nebulized racemic epinephrine, steroid

Laryngotracheal (Subglottic) Stenosis Occurs in 90% of prolonged endotracheal intubation

Lower incidence in preterm infants and neonates due to relative immaturity of cricoid cartilage

Pathogenesis: ischemic injury secondary to lateral wall pressure from ETT, edema, necrosis and ulceration of mucosa, infection

Granulation tissues form within 48hrs leads to scarring and stenosis

• More anatomical fit • Sealing at low pressures• More distal position• Greater permeability for nitrous

oxide

• For neo ≤ 3 kg and infants ≤ 1 yr, ID = 3.0 mm

• For children 1 to 2 years of age, ID = 3.5 mm

• For children ≥ 2 years, ID = Age/4 + 3.5

• Post-intubation croup was 0.4% (2/500 children)

Rigid LaryngoscopyThe retromolar, paraglossal, or lateral approach to rigid laryngoscopy utilizing a straight blade.

LEMON Look

Short neck, large tongue, micrognathia

Evaluate 3-3-2 3 finger breadths of mouth

opening 3 finger breadths submental to

hyoid 2 finger breadths hyoid to thyroid

Mallampati Obstruction Neck mobility

LMAs (laryngeal mask airway) I-LMAs (intubating LMA) Rigid bronchoscopy Flexible bronchoscopy Lighted stylet Bullardscope Fiberoptic intubation Surgical airway Combitube Bougie

Pick one or two and practice

Helpful for infants & children with immobile or shortened necks.

Either by an assistant or the laryngoscopist.

Supraglottic airway device developed by Dr. Archie Brain

Useful in difficult airway situations

Conduit of Drug Administration (ie. Surfactant) Types of LMAs: Classic LMA, Flexible LMA, ProSeal LMA,

Intubating LMA Contraindications: Full Stomach, Gag reflex, FBs, Airway

obstruction, High ventilation pressure

Disadvantages: Laryngospasm, aspiration

LMA Size Weight Max. Cuff Vol. (ml)

ETT Size (IDmm)

1.0 ≤ 5 kgs 4 3.5

1.5 5 – 10 kgs 7 4.0

2.0 10 – 20 kgs 10 4.5

2.5 20 – 30 kgs 14 5.0

3.0 30 – 50 kgs 20 6.0

4.0 50 – 70 kgs 30 7.0

5.0 > 70 kgs 40 8.0

INSERTION TECHNIQUE

Only sizes 3, 4, 5

Same rules and sizing as LMA

Need special armored tube for intubation

Leave LMA portion in place in field

Laryngeal Tube Latex-free, single-lumen silicone tube, which is closed at distal end

Two high volume-low pressure cuffs, a large proximal oropharyngeal cuff and a smaller distal esophageal cuff

Both cuffs inflated simultaneously via a single port

Situated along length of oropharynx with distal tip in esophagus

Sizes 0-5, neonates to large adults

Cobra PerilaryngealAirway

Perilaryngeal airway device with distal end shaped like a cobra-head

Positioned into aryepiglotticfolds and directly seats on entrance to glottis

Inflation of the cuff occludes the nasopharynx pushing the tongue and soft tissues forward and preventing air leak

Available in sizes pediatric to adult ½ to 6

Not useful in most kids

Easy to place

Two sizes Small (4 to 5.5 feet tall) Regular (over 5.5 feet tall)

Contraindications Gag reflex Esophageal disease Caustic ingestions FBs/Airway obstruction

Two person technique

Replaces stylet

Able to use with poor view

Intubate over it

Outer diameter – 5 mm

Total length – 60 cm

Small upturned distal end bend at 38⁰ helps in passage

KIWI GRIP

SHIKANI FIBREOPTIC SCOPE

Can’t ventilate

Can’t intubate

LMA contraindication (massive orofacial trauma) or not working

All intervations FAILED

< 5 years old Needle cricothyrotomy and bag ventilation

5 to 10 years old Needle cricothyrotomy and bag ventilation

If oxygen saturation is inadequate, Transtracheal jet ventilation

> 10 years Needle cricothyrotomy with TTJV

Surgical cricothyrotomy – Contraindicated in < 10 yrs

3-5cc syringe: 1-2cc saline OR 12- or 14-gauge IV

Identify CTM and stabilize/prep larynx Insert needle on syringe, direct inferiorly

Large bore needle (12-16 gauge) Catheter over needle

Advance catheter Connect to TTJV (BVM for infants - 3.0 ETT)

Oxygen pressure (20-30 psi) 1 second on/2-3 seconds off

Complications (Similar to other cricothyrotomy) Bleeding Pneumothorax, Subcutaneous Emphysema, Pneumo-mediastinum Barotrauma Esophageal, Laryngeal or Tracheal Injury Obstruction Infection Subglottic stenosis

Beneficial for children who cannot be “ventilated” by other route

Percutaneous needle cricothyrotomy provides only a mean for oxygen insufflationand does not reliably provide adequate ventilation.

TTJV

Broselow-Luten Emergency System Color-coded bags with equipments

Quicker, more efficient

Most accurate 3.5 - 25 kg

Congenital Neck Masses (Dermoid cysts, cystic teratomas, cystic hygroma,

lymphangiomas, neurofibroma, lymphoma, hemangioma)

Congenital Anomalies (Choanal atresia,tracheoesophageal fistula,

tracheomalacia, laryngomalacia, laryngeal stenosis, laryngeal web, vascular ring, tracheal stenosis)

Congenital Syndromes (Pierre Robin Syndrome, Treacher Collin, Turner,

Down’s, Goldenhar , Apert, Achondroplasia, Hallermann-Streiff, Crouzan)

Inflammatory (Epiglottitis, acute tonsillitis, peritonsillar

abscess,retropharyngeal abscess, laryngotracheobronchitis,bacterialtracheitis,adenoidal hypertrophy,nasal congestion, juvenile rheumatoid arthritis)

Traumatic/Foreign Body (burn,laceration,lymphatic/venous obstruction,fractures/dislocation, inhalational injury, postintubationcroup (edema),swelling of uvula

Metabolic (Congenital hypothyroidism, mucopolysaccharidosis, Beckwith-

Wiedemann Syndrome,glycogen storage disease, hypocalcemia laryngospasm)

CYSTIC TERATOMA

Occurs in 1/ 3000-5000 births

Most common type is the blind esophageal pouch with a fistula between the trachea and the distal esophagus (87%)

Feeding difficulties (coughing, choking and cyanosis) and breathing problems

Associated with congenital heart (VSA, PDA, TOF), VATER, GI, musculoskeletal and urinary tract defects

Complete nasal obstruction of the newborn

Occurs in 0.82/10 000 births Unilateral nare (right>left) During inspiration, tongue

pulled to palate, obstructs oral airway

Bilateral choanal atresia is Airway Emergency

Death by asphyxia Associated with other

congenital defects

Occurs in 1/8500 births

Autosomal recessive

Obstruction is usually at the nasopharyngeal level

Mandibulofacial dysotosis

Occurs in 1/10 000 births

Unilateral Absent Thumb

Trisomy 21 Occurs in 1/660 births

Exomphalos MacroglossiaGigantism Syndrome

Overgrowth Syndrome

Occurs in 1/13000-15000 births

Short Arm of Chromosome 11p15

Autosomal dominant

Haemophilus influenzae type B Occurs in children ages 2-6 years Disease of adults due to widespread H. influenza vaccine

THUMB SIGN

CHERRY RED EPIGLOTTIS

Parainfluenza virus

Occurs in children ages 3 months to 3 years

Barking cough

Progresses slowly

Medically managed with oxygen and mist therapy, racemic epinephrine neb and IV dexamethasone (0.25-0.5mg/kg)

Indications for intubation: progressive intercostal retraction, obvious respiratory fatigue, and central cyanosis

CLEFT LIP AND PALATE Most common congenital

face malformation

APERT AND CROUZON Maxillary hypoplasia

Nasopharyngeal airway compromise

GOLDENHAR SYNDROME

Unilateral anomalies

Higher incidence of airway anomalies

LARYNGOMALACIA

A sequence between fully formed to atresia

LARYNGEAL WEB

TRACHEAL ATRESIA

Survive only if tracheoesophagealfistula or emergent tracheostomy done

SUBGLOTTIC STENOSIS

HEMANGIOMA OR LYMPHANGIOMA Only about 30% present at

birth

RULES

“Use your common sense”

“ Do not continue to do the same thing and expect different results’’

“Easier comes first”

“Each difficult intubation is a different”